Differential gearing.



J. Fj.--}PARR0TT. DIFFERENTIAL GEARING. APPLICATION- FILE!) MAR. 4.51914.

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PtentedNov. 3o, 1915.

LF. PARROTT. DIFFERENTIAL BEARING. `APPLICATION FILED MAR. 4, 1914.

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Patented Nov, 30, 1915.

UNITED sTATEs PATENT OFFICE.

JOI-IN F. PARROTT, OF PORTLAND, OREGON, .ASSIGNOR 0F ONIl-l-I-lAIllf` TO G. P. HENDERSON, OF PORTLAND, OREGON.

DIFFERENTIAL GEARING.

Specification of Letters Patent. Patented NGV. 30, 1915.

Application filed March 4, 1914. Serial o. 822,535.

-To all whom t may concern.'

Be it known that I, JOHN F. PAnnoT'r, a citizen of the United States, and a resident of the city of Portland, county of Multnoniah, State of Oregon, have invented a new and useful Improvement in Differential Gearing, of which the following is a specification.

, My invention relates to the transmission mechanism of motor driven vehicles'and has particularly to do with the differential gear- -ing whichv permits the driven wheels to re- 4is to provide devices which will maintain the driving strain on both wheels though permitting one wheel to run faster than the other.. To this end my devices are so contrived\that when the vehicle is going around a curve, and the inside driven wheel slips,

the driving strain will be instantly transmittedto'the outside idling wheel; and when the vehicle is on a straightway, both wheels being driven, and one wheel slips, the driving strain will be maintainedfsteadily on kboth wheels, instead of allowing the nonslipping wheelfto idle. The increased trac- 355 tion. will then assist in pulling the vehicle dut; of the hole.

A `further object of myinvention is to provide improved means for automatically revel-sing the driving connections between the diii'erential and the rear axle whenever the engine is reversed. i

The details of my invention are fully shown in the accompanying drawings, in which:

Figure 1 is a plan view of a part of the transmission mechanism embodying my invention; a portion of thek differential case is broken away so as to show the relative arrangement of the innerparts; Fig. 2 `is a proveinent in differential gearing; Fig. 3 is rear elevation, on a larger scale, of my ima side elevation, slightly reduced, of the parts shown in Fig. 2; thel parts -are .1arranged so as to rotate the divided ]ack shaft or rear axle imceunter-clockwise direction,'

as indicated by the arrow; and Fig. fl is another view of the parts shown inA Fig. 3. In this View the engine has been reversed and the parts'are shownin position to drive the divided jack shaftelockwise.

I have illustrated myinvention as used 0n the jack-sliaft of an automobile truck, but of course the same niayillso be used on the rear axle of any motor driven vehicle when the type of the latter will permit such location of the differential. The propeller shaft of tlievehicle is represented by a in Fig. 1 and has keyed on its rear endA a bevel pinion '1). Any convenient lforni of variable speed two abutting sections, f, g, of the jack-shaft,

each section being rotatably mounted on roller bearing elements h in the differential gear casing. See Fig. l. A bevel gear, z', is-loosely journaled onxtlie abutting ends of the jack-shaft sectionssaid gear meshing with and being driven .by the bevel pinion b of the propeller shaft v d A pin, j, is journaled in the web of sai-1A gear z'. On the pin j is rigidly mounted afdouble-ended rockerarni r, bearing on itsextremities the lateial pins m, n, and the latter bearing friction rollers m', n.

pin y' are loosely mounted the double-ended pawls, r, s, the extremities of which are madei On tliefopposite ends of the with small longitudinal toes, as shown by s2, s3'. Restraining springs, r,'s, are also fixed on the opposite `ends of the pin j, and their ends are made fastto the arms of the pawls,r, s, respectively, as shown in Figs. 3 andi. These springs are adapt-edto normally hold said pawls. r, s, in position on the pin j, at tlie-saine time permit them Ceitain independent movement. On each 'of the jack-shaft sections. f, g. are keyed the ratchet wheels. t, u. adapted to be engaged by the pawls, r, s. The y'root of each ratchet tooth is recessed (u) on both sides, as shown in Figs. Band 4, said recesses ,forming seats for said toes on the extremities of the pawls, r, s. The purpose offthis construction is to prevent the working of the pawls from springing out of engagement with the ratchet wheels. .On the jackshaft section, g, adjacent the ratchet wheel u 1s fixed a.

cam-plate c. A keeper, w, is pivotally mounted in the web of the gear, e', (see Figs.

the pin y'.

3 and Ll) at a point diametrically'opposite The arm to of this keeper is connected to the double-ended lrocker-arm /c by a link and the arm l102 has a bevel face adapted to bear against a flat spring x, supported on the gear e'. l'The spring a is made relatively weaker than the spring 1'?, for a reason to be explained later. The bevel face of the keeper 'a is so formed that a small movement of the latter will cause the arm Q02 to bear against the spring a: to the point where the vertex of said bevel faces is slightlyover center. The pressure of the. spring will then throw the keeper yw to the position shown in Fig. l. The rocker-arm being connected by the rod it" with the keeper lw and the latter bearing against the spring surface .1", when the keeper is in clined to either side it will spring over to said side and hold the rocker-arm in yposition. The pawls i', s, being pivoted on the axis of the rocker-arm and yieldingly connected therewith through the medium of the restraining springs r', s', will have a tendency to follow the movement of the rockerarm.

-Now brieflyv describing the action of my device, the cam plate r rotates with the ackshaft sectfon g; the double-ended rockerarm traveling with the bevel gear 2'. Assunifng that the gear z' is being driven in the direct on indicated by the arrow A in Fig. 3. both pawls r and .s will be engaged with the respective ratchets t and u, and the axle potions and f/ will thereupon be driven at the same speed. If the machine turns to the left. the axle portion f will be on the outside of the curve and will therefore be required to travel faster than the axle por'- tion y. r1`his faster travel will cause the pawl r to idle against the' action of the spring i", while the pawl .5l remains in engagement with and drives the slower running ratchet u. As soon as the axle portion f has resumed the speed of the axle portion g, the pawl r will spring hack into working engagement with the ratchet t. and both axle sections will theirbe positively driven at the same speed. lf. now. the machine turns to the right. the axle portion f/ will he on the outside of the curve and will therefore` be required to travel faster `than the axle portion rlhis faster speed of travel will allow the paw] .sto idle over the faster running ratchet u. and the pawl 1 will remain in en- Igrgement with and drive the slower running ratchet t. The faster speed of rotation of the axle portion g will cause the cam'tl to run ahead of the lgear rz' and as it passes under the rollerm. the rocked arm 7.: will be partially rocked so that it will merely ride over the cam 1E. As soon as the cam v has passed away from the roller m, the arm will resume its initial position as shown in'F ig. 3. The reason for this return of the arm k to its initial position instead of being thrown completely over center to the p0Si tion shown in Fig. l is that the pawl 1' remains in engagement with the slower running ratchet t, on account of having its toe r2 engaged with'the recessed portion of the tooth of said ratchet. The rotation of the pin j, due to such partial rocking of the arm la, will work against the spring r2 and the latter being stronger than the spring will cause the pin j and thereby the arm 7c, to return to their initial positions. It will thus be seen that when the axle portion g is running faster than the axle portion the pawl s and the `arm 7c, will merely idle over the ratchet u andcam zi respectively. In order that the arm la will be thrown completely over centerto the position shown in Fig. l, both pawls must idle, which will only occur momentarily when the direction of ro tation of the gear is reversed, and when this occurs, the spring will not be resisted .by the spring ri and will, therefore, act to throw the arm la completely over center' when the cam r partially rocks said arm.

'hen the vehicle is on a straightway and one of the wheels becomes mired, it will be prevented from slipping by the ratchet Aengagement of the other wheel. In present structures. when one wheel slips, the other remains idle, whereas in mine, the n0n slipping wheel will take up the driving strain and be driven synchronously with the slipping wheel. The increased traction will then pull the vehicle over the slippery portion of road.

Another added advantage in this type of differential is that when the vehicle is coasting down a grade, the differential will automatically adjust itself to 'a working-position. The rotation of the vehicle wheels will drivethe differential gear, so that when the clutch of the propeller shaft is in engagement the latter and the engine crankshaft will be driven. In this wa)T the en gine may be lcooled off and will act as a brake to retard the velocity of the vehicle.

For convenience the bevel gear b is referred to in some of the claims as the primarv driven gear. l

I claim: 1. In power transmitting mechanism, the combination with the-primary driven gear and a divided driven axle, of a driving element on each member of such divided axle,

. a gear loose on the divided driven axle. such said loose gear, adapted to operate said en.

gaging means simultaneously and to there'- by cause,l tle driving of the divided axlev with tlie"lo'o se gear; said engaging means adapted'to permit the faster running mem-\ ber of the divided axle to run idle for the time; means on the loose gear for so operating said engaging means as to cause the driving ofthe members of the divided axle in i the same direction as said looser gear; and means for temporarily holding said engaging means as positioned. y

2. In power transmitting mechanism, the combination with the primary driven gearV vand a divided driven axle, of a ratchet Wheel fast on each member of such divided axle, a

gear loose on the divided driven axle, such gear being driven by the primary driven gear; paWl elements carried 'by such loose gear for engaging said ratchet Wheels of the divided axle;said pawls and drivingrelements adapted to drive the divided axle -in p either direction; spring-controlled means lactuated by the rotation of said loose gear adapted tok-operate said pawl elements simultaneously and to thereby cause the driving of the divided axle with the loose gear; :said pawl elements adapted to permit the faster running member of the divided axle to run' idlefor the time; and means on the loose gear for so operating said pawl elements as to cause the drivingv'of the members of the divided axle in the same direction 'as said loose gear. e 3. In power transmitting mechanismythe' combination with the primary driven gear and a divided driven axle, of af ratchet Wheel. fast on each member of such divided axle, a gear loose on the divided driven axle; 'such gear .beingdriven by the primary driven gear; paWl elements carried by such loose gear for engaging said ratchet Wheelsof the divided axle; saidy pawls and driving elements adapted to drive thevdivided axle in either direction; spring-controlled means. A45

actuated by the rotation of said loose gear adaptedto operate said pawvl elements simultaneouslv and to thereby cause the driving of the divided axle with the loose gear; said pawl elements vadapted to permiththe to run idle for the time: means on the loose gear for so Ioperating said pawl elements as to 'ca-use the driving of the members 'of the divided axle-in the same direction assaid loose gear; and means for temporarily holding said engaging means as positioned.

4. In power transmitting mechanism, the combinationfvvith the primary driven gear, of a divided driven axle, driving elements mounted thereon; a loose gear on saiddivided axle; a pin journaled in said loose gear and extending from its opposite faces: dpuble-ended arms. fast on the ends of said pins for engaging with said driving elements; a double-ended vmember pivoted over faster running member of the divided axle each of said arms and adapted for engaging with said driving elements; restraining springs adapted normally to cause the pivot;

ed members to assume the inclination of said arms; projections on the extremities of said arms; a cam plate fast on the divided axle for engaging with said projections on said arms and to thereby tilt the latter; and

vmeans for temporarily holding said'arms in position' astilted.

5. In power transmitting mechanism, the combination with the primary driven gear, .of a divided driveir'axle, driving elements inonnted thereon;a loose gear on said divided axle; a-pin journaled in said loose gear and extending: from its yopposite faces;

double-ended arms fast on the ends (Lf saidA pins for engaging with said driving elel ments; a double-ended member pivoted vover each of said arms and adapted for engaging with said driving elements; restraining springs adapted normally to cause the y pivoted"members to assume the inclination of said arms; projections on the extremities of Said arms; a cam plate fast on the divided.v

axle for-engaging with said projections on said arms and to thereby tilt the latter;`

means for preventing the vdisengagement of the Working ends of the paWls from the ratchet Wheels until the tilting of the pawls; and means for Itemporarily holding said arms in position as tilted.

6. In power transmitting mechanism, the

combination with the primary driven gear,

of a divided 1 driven axle, rathet v vheels mounted thereon;a loose gear on said d1- vided axle; a. pin journaled in said .loose -`gear and extending from its opposite faces;

double-ended arms fast on the ends'of said pins for engaging with said ratchet Wheels; a double-ended pawl pivoted over each of said arms and adapted for-.engaging With` said ratchet Wheels; restraining springs adaptednormally to cause the pawls to assume the Ainclinationoi said arms; projec# tions on the extremities of said arms; a 'ca-m plate tast on the divided axle for engaging ifio with said projections on said arms and to therebv'tilt thelatter; means for preventing theV disengagement of the Working ends of the p'awls from the ratchet Wheels until the tilting of the pawls'; and means for temporarily holding said arms in positionas tilted. 7.`In power-' transmitting mechanism, the

, combination with a variable speed gearing,

oi"l a divided'driven axle', ratchet Wheels mounted thereon; a loose gear on said-divided axle; a pin journaled in said loose gear and extending from its opposite faces; double-endet"V arms fast on the ends of said pins engaging with said ratchet Wheels; a double-ended pawl pivoted over each of 'said arms and adapted for engaging with said ratchet, Wheels; restraining springs adapted iis' :normally: to Y cause theY paivls Atn assiime the inclination of said arms; projectioiison the extremities of said arms; and a cam plate -fast on the diyfided axle-for engaging with said projections onsaid arms and to thereby tilt the latter.

.hgnf' power transmitting mechanism, the -iiomoination with a variable speed gearing,

,of Va divided driven axle, ratchet wheels LH;

vmounted, thereon; a loose gear on said diijided axle; apin Journaled in said loose gear and extending from its opposite faces;

doubleended arms fast on the ends of 'said 'pins for' engaging with said ratchet Wheels; a dfoble-ended paWl pivoted over each of said .arms and adapted for' engaging with said ratchet wheels; restraining springs adapted normally. to causent-he paWls to assume the inclination of said arms; projections on the extremities of said arms; a cam plate fast on the divided axle fo/i engaging with said projections on said arms and to' thereby tilt the latter; and means for temporarily holding said4 arms in position as tilted.

9. In power transmitting mechanism, the

combination with avariable speed gearing, of a divided driven axle', ratchet wheels mounted thereon. a loose gear on said di-v vided axle, a pin joiiinaled in said loose gear 'and extending from its opposite Jfaces; dou- -ble-ended arms tast on the ends of said pins gagement of the Working ends of the paivlsy from the ratchet Wheels until the tilting of lthe paivls; and means for temporarily hold-l ing said arms in position as tilted.

l JOHN F. PAR-HOTT.

Witnesses VM. C. SCHMITT, Cncii. LONG.

Copies of this patent may'be obtained for five cents each, 'ny addressing the Commissioner'of Patents,

' Washington,4 1)..0. 

